Charged particle beam apparatuses are known to include, for example, scanning electron microscopes that emit an electron beam onto a surface of an object such as a semiconductor wafer and a glass substrate and use a generated secondary electron beam, and electron beam lithography apparatuses for forming a fine wiring pattern on an object.
Japanese Unexamined Patent Application Publication No. 7-161329 discloses an electron beam apparatus which includes an electrostatic lens that allows a single axis electron beam to pass through.
When a plurality of electrostatic lenses are arranged, for example, in order to improve the throughput of the apparatus, it is difficult to align the plurality of electrostatic lenses since the electrostatic lenses are mechanically positioned. This may lead to variation in the distance between the electron beams which pass through the electrostatic lenses and often generates a non-irradiation area of the electron beam between the irradiation areas. Such a non-irradiation area often causes a non-observation area to be generated in the scanning electron microscope and a failure in wiring pattern to be occurred in the electron beam lithography apparatus.
Therefore, an electrostatic lens which improves an irradiation accuracy of an electron beam while satisfying the need for higher throughput is needed.